Preliminary results show Aaron Peskin is on track to defeat incumbent District 3 Supervisor Julie Christensen, 53 percent to 43 percent, according to the San Francisco office of elections, with 100 percent of precincts counted.

However, an estimated 42,000 vote-by-mail ballots still need to be counted before the election results can be confirmed.

Peskin was in his spirits at his election party Tuesday at Club Fugazi. Hw clasped his hands and raised them above his head. “Let me just say the following words, from the bottom of my heart: We did it,” he said.

The preliminary results show Incumbent Mayor Ed Lee has defeated his opponents with 57 percent of the vote. His closest opponent, Francisco Herrera, has 15 percent of the vote.

Measure F, the short term rentals regulations proposal, lagged with 55 percent against and 45 percent supporting it.

In the sheriff’s race, Vicki Hennessy is on track to defeat incumbent Ross Mirkarimi, garnering 61 percent of the vote, comparedv to 33 percent.

UPDATE 10:15 P.M.:

With just over 40 percent of precincts counted, in the Board of Supervisors District 3 race Aaron Peskin remains ahead with roughly 51 percent of the vote, compared to incumbent Julie Christensen’s 44 percent.

Measure F, the short-term rentals regulations proposal, is behind with roughly 58 percent of voters against the measure, and 42 percent supporting it.

“Because of you we won’t have neighbors spying on other neighbors,” Assemblyman David Chiu told a packed crowd of No on F supporters at the Oasis nightclub Tuesday night.

UPDATE 9:38 P.M.:

Former Board of Supervisors President Aaron Peskin is pulling further ahead of incumbent challenger Julie Christensen in the bid to reclaim his District 3 seat on the board, according to the latest election results.

With just over 20 percent of the votes counted, Peskin was leading with 51.36 percent of the votes. Christensen had 44.47 percent.

State Sen. Mark Leno, a Peskin supporter, called the early results “encouraging.”

Peskin maintained that he is proud of his campaign.

“We are cautiously optimistic,” Peskin said. “We’ve had hundreds of very motivated volunteers in every community of this district, from Chinatown to North Beach, Upper Tenderloin to Nob Hill.”

Meanwhile, Mayor Ed Lee continued to lead with 61.37 percent of the votes, and sheriff hopeful Vicky Hennessy advanced further ahead of incumbent Ross Mirkarimi with 62.53 of the votes, compared to Mirkarimi’s 31.11 percent.

UPDATE: 8:40 P.M.:

The 65,923 vote-by-mail ballot results released just after 8:30 p.m. Tuesday show Mayor Ed Lee strongly leading in his bid for re-election with 66.83 percent of the votes.

Sheriff hopeful Vicky Hennessy, who is trying to claim the seat from incumbent Ross Mirkarimi, is also ahead with 64.24 percent of the vote-by-mail results. Mirkarimi, however, is far from ready to concede his post.

“It’s very early. We’ll see how it goes,” Mirkarimi said outside his election party Tuesday night.

Hennessy, meanwhile, thanked supporters at her election party while cautioning them to await the final count.

In a tighter race, Board of Supervisors District 3 candidate Aaron Peskin is slightly ahead of his incumbent challenger Julie Christensen with 49.1 percent of the votes. Christensen has 46.5 percent.

Peskin said Tuesday night that he was proud of his campaign but was not ready to reach any conclusions in the election.

“It’s way too early,” he said. “I feel like we’ve run a great grassroots campaign. We never ran one negative ad.”

Contentious housing-related measures Proposition F, which seeks to further regulate short-term rentals, and Proposition I that hopes to impose a temporary pause on market-rate development in the Mission District, are both losing. Opponents of Prop. F brought in 61.03 percent of the vote-by-mail results, while 63.96 percent voted against Prop. I.

Meanwhile, other mayoral candidates were not discouraged by Lee’s strong lead, noting more progressive votes are expected to be tallied later in the night.

“For me personally, I want to put up a good fight, show some good numbers and let the bastards know they can’t grind us down,” said Stuart Schuffman, who received 6.72 percent of the vote-by-mail ballots.

Vote-by-mail results comprise 14.75 percent of the electorate.

John Arntz, director of the Department of Elections, said the ballots that won’t be counted Tuesday include 12,000 vote by mail ballots received Tuesday in the mail, the 1,000 ballots cast at City Hall and the estimated 30,000 vote by mail ballots dropped off at polling stations.

Click here for complete election coverage from the San Francisco Examiner, and check back for breaking updates as more results are released.